Flaying devices



June 26, 1956 w, w z 2,751,680

FLAYING DEVICES Filed May 25, 1954 2 Sheets-Sheet l INVENTOR Wa/zer"4929/ ATTORNEX W. WEZEL FLAYING DEVICES June 26, 1956 Filed May '25,1954 2 Sheets-Sheet 2 R O N E V m ATTORNEY United States Patent FLAYIN GDEVICES Walter Wezel, Maulbronn, Germany, assignor to firm Schmid &Wezel, Maulbronn, Wurttemberg, Germany, an openpartnership organizedunder the laws of the German Federal Republic Application May 25, 1954,Serial No. 432,161

' Claims. (Cl. 30-219) The present invention relates to mechanicalflaying devices.

In flaying devices of the type in question which are found to beparticularly useful in abattoirs, the manual force ordinarily requiredfor severing the skin of a slaughteredanimal from the carcass isreplaced by mechanical power. Nearly all mechanically actuated devicesof this nature comprise two round, toothed cutting discs which, whileoscillating past each other, by means of the keenly faceted teeth cutthrough the connecting tissue between skin and flesh. The cutting dis-csare fastened to, or held by, a suitably shaped hand piece which,usually, contains the gears for actuating the cutting discs. The gears,in turn, are driven by means of a flexible shaft attached to a suitablepower source, such as an electric motor.

The present invention is primarily concerned with the construction ofthe cutting discs. The novel features which I consider characteristic ofmy invention are set forth with particularity in the appended claims.The invention itself, however, and any additional objects and advantagesthereof will be best understood from the following description of apreferred embodiment when read in connection with the accompanyingdrawings in which:

Fig. 1 is a partly sectional side elevation of the device, with thehousing removed;

Fig. 2 is a sectional view on the line II--II in Fig. 1;

Fig. 3 is a side view of a cutting disc;

Fig. 4 is a sectional view on the line IV--IV in Fig. 3;

Fig. 5 is a detail view of one of the cutting teeth; and

Fig. 6 is an exaggerated illustration of the position of the teeth ofthe two blades with respect to each other.

Referring more specifically to the drawings, the numeral 11 indicates ahand grip, usually made from wood or plastic, 12 refers to a housing and13 to a housing cap made from the same material as the hand grip. Heldbetween the housing and the housing cap are two cutting discs 14, 15which are rotatably mounted next to each other on a spacer ring 16,positioned about the cap nut 17 held by the cap retaining screw 18.

A bearing cap 19, fastened by means of the screw 20, retains the ballbearings 31 of an eccenter shaft 32 fitted within a needle bearing case33. The other end of the eccenter shaft is held by a similar ballbearing. Mounted on the eccenter shaft are two driving levers 34, 35,adapted to oscillate the cutting discs 14, 15, respectively, in oppositedirection and each over an angle of about 10. The numerals 36, 37indicate cut-outs in the housing elements 12, 13 to permit oscillationof the driving levers. The latter are held in position and spaced fromeach other by means of the end washers 38 and the spacer gasket 39.

A bevel gear wheel 40, keyed at 41 to the eccenter shaft and inengagement with the bevel gear 42 mounted at the end of a shaft 43serves to actuate the said eccenter shaft and, therethrough, the drivinglevers and the cutting discs. The gear assembly is secured within thehousing by means of staybolts and nuts 44 and 45, respectively. Theshaft 43, held by ball bearings 46 and 47, is provided with a "ice fishtail jaw 48- at the free end for coupling a flexible shaft thereto. I

The cutting blades of the afore-described preferred embodiment have adiameter of about 2.5 inches and are geared to make about 4,200oscillations per minute, to cut through connecting tissue while theteeth of the blades pass each other. It is to be noted, in thisconnection that, while the edges of the teeth must be sharp, the pointsshould be dull in order to prevent cutting of the skin.

Until now, cutting discs such as the discs 14, 15 have been employed.These discs are entirely flat so that the interior surfaces or, atleast, a substantial area of the interior surfaces of the discs are infull contact with. each other. This design. has two disadvantages: inthe first place, blood and other oifals entering between the discsfrequently cause the surfaces of the discs to stick together, evenduring such. short intervals as A: to V2 hour, thereby producingv asevere strain upon the flexible shaft and the motor when the work isresumed; secondly, the teeth of the discs must be sharpened veryfrequently which requires skilled. labor and is extremely timeconsuming.

In accordance with this invention, the cutting discs are provided withinner surfaces that are. hollow-ground. Moreover, by suitable means thetwo discs are pressed against each other. As a result, the facets of theteeth of the discs pass each other in the same manner as the cuttingedges of a pair of paper shears. The advantage gained from this noveldesign is (a), a self-sharpening effect and (b), a protection againstthe entry of blood and other oflals between the discs.

Thus, according to the present invention, the interior surfaces orsubstantial portions of the interior surfaces of the discs are no longerin contact with each other over an area, but only along an undulate lineat the cutting edge and the teeth of the two discs act against eachother like a multiplicity of shears or scissors the elements of whichare continuously exchanged in position. As with shears or scissors whichhave blades of a certain elasticity that, instead of being perfectlyplain and parallel to each other, are bowed so that the cutting contactmoves from the hilt to the point, the cutting contacts of the presentdevice move from the respective bases of two adjacent teeth to the tipof the facets of these teeth and down again to the other bases.

Discs of this novel type are the discs 14a and 15a illustrated in Figs.3 and 4. In order to keep the discs pressing against each other,circularly arranged series of recesses, such as the recess 50, areprovided at the interior surface of at least one of the housing elements12, 13, but preferably at both of them. Mounted within these recessesare spring-loaded ball bearings, such as the ball bearing 51. By meansof pressure exerted by the springs, the balls, being in rolling contactwith the cutting discs or at least with one of the cutting discs, causethese cutting discs to remain in close peripheral proximity to eachother.

Until now, cutting discs of a body thickness of about 1.5 mm.,diminishing to a thickness of 0.75 mm. at the peripheral section and atthe teeth have been considered to be most practical. I have now foundthat the efiiciency and the output can be materially increased at lesseffort on the part of the operator, if the cross-section of the teethportion is further reduced, say along the line 7 shown in Figs. 5 and 6,resulting in elastic teeth having a thickness of only about 0.5 mm.

Fig. 6 depicts in an exaggerated manner the interception of the facets54 and 55 of the discs 14a and 15a in order to attain the desiredself-sharpening of the edges.

Having described my invention, I claim:

1. In a flaying device comprising a hand grip, a housing consisting oftwo shells, two toothed cutting discs mounted rotatably within, andextending peripherally from, the said housing, an eccentric mounted onan eccentric shaft within the said hand grip, fastened to the saideccentric two driving levers, each adapted to oscillate one of the saidcutting discs over an arc of about l0" against the other, a first bevelgear keyed to the eccentric shaft, and in operative alignment with thesaid first bevel gear a second bevel gear mounted at one end of a driveshaft positioned concentrically within the said hand grip, theimprovement consisting of two hollow ground cutting discs the teeth ofwhich are adapted to intercept each other with a self-sharpening effectupon oscillation of the said discs in close proximity with each otherand mounting the said discs in close proximity with each other.

2. In a fiaying device according to claim 1, the improvement comprisingmeans of pressing the said hollow ground cutting discs against eachother.

3. In a fiaying device according to claim 1, the improvement consistingof circularly spaced recesses provided at the interior surface of atleast one of the said housing shells, and, mounted within the saidrecesses, springloaded ball bearings adapted to exert pressure againstthe adjacent hollow ground cutting disc to keep the said cutting discsin close peripheral contact with each other.

4. In a fiaying device comprising a hand grip, a housing consisting oftwo shells, two toothed cutting discs mounted rotatably next to eachother within, and extending peripherally from, the said housing, aneccentric mounted on an eccentric shaft within the said hand grip,fastened to the said eccentric two driving levers, each adapted tooscillate one of the said cutting discs over an arc of about 10 againstthe other, a first bevel gear keyed to the eccentric shaft, and inoperative alignment with the said first bevel gear a second bevel gearmounted at one end of a drive shaft positioned concentrically within thesaid hand grip, the improvement comprising elastic, hollow groundcutting discs provided with faceted teeth in linear cutting contact witheach other whereby, as the cutting discs oscillate against each other,the linear cutting contact commences at the respective bases of twoadjacent discs, ascends to the tips of their facets and descends to theopposite bases, and means pressing at least an operative portion of saidcutting discs against each other.

5. In a cutting device according to claim 4, the improvement consistingin providing opposite cutting discs sufiiciently thin to cause bendingof the peripheral area of the cutting discs toward each other.

References Cited in the file of this patent UNITED STATES PATENTS1,945,247 Wezel Jan. 30, 1934 2,317,177 Carissimi Apr. 20, 1943 FOREIGNPATENTS 678,605 Great Britain Sept. 3, 1952

